Swimming is the self-propulsion through water for recreation, sport, exercise, or survival, relying on coordinated limb and body movements to achieve buoyancy and hydrodynamic thrust. It is a top recreational activity offering benefits like strengthened cardiovascular health and muscle flexibility, and it is suitable for all ages, with swimming lessons even compulsory in some educational curriculums. As a formalized sport, it is featured in every modern Summer Olympics, where the front crawl (freestyle) is widely regarded as the fastest stroke. The science behind swimming reveals that the human body's near-neutral buoyancy (relative density of 0.98) makes it a low-impact exercise, and hydrodynamics dictates that reducing water drag is significantly more efficient than increasing stroke power. However, swimming poses risks like drowning from panic or exhaustion, leading most facilities to employ lifeguards, while swimmers often use specialized equipment such as goggles, fins, and snorkels to enhance performance and safety.